A group of pregnant women are being studied for the purpose of investigating the possible influence of body composition on the outcome of pregnancy. Measurements include assays of lean body mass (LBM) and fat early and again late in pregnancy, Anthropometric measurements, dietary history, blood sample for hemoglobin, protein, vitamins; the neonates are weighed and measured at birth. Results to date show that there is considerable variation in the rate of gain of body weight, LBM, and fat during pregnancy, and as would be expected birth weights vary too. Very few of our subjects demonstrate abnormalities in nutrient intake or in serum protein, folate or vitamin B-12 levels, although about 10% are mildly anemic; however about a quarter of them use alcohol and/or tobacco. Ninety-two infants have been born thus far, and this sample is too small to warrant statistical analysis at this time. This study is scheduled to continue for additional 15 months, by which time we hope to have a sufficient number of subjects.